1. Field of the Invention
The present invention relates to a stabilizing agent for enzymes, to a composition containing the agent, and to a kit or a similar product containing the agent.
2. Description of the Related Art
Generally, functions of enzymes are known to be related to a stereostructure thereof, and the functions are known to be lost or inactivated as a result of change in stereostructure during storage thereof. Since enzymes are generally supplied in the form of lyophilized products, a variety of studies have been carried out on methods for preventing deactivation or denaturation of enzymes during lyophilization. Among such methods, addition of an amino acid or protein such as sodium glutamate, albumin, or skim milk; addition of a sugar such as sucrose or maltose; addition of a reducing agent such as glutathione or mercaptoethanol; addition of a polyhydric alcohol such as glycerol or sorbitol, and a similar method are generally known.
Techniques for stabilizing enzymes through employment of a plant-derived protein or a degraded product thereof are also disclosed. For example, WO 96/11264 discloses a technique in which a hydrolyzate of protein derived from wheat, soybean, etc. is employed as a stabilizing agent for transglutaminase, which is an enzyme widely employed in food processing industry. However, the document neither discloses nor suggests stabilization of enzymes for use in analysis (hereinafter referred to as analytical enzymes).
At present, bovine serum albumin (BSA) is generally employed as a stabilizing agent for enzymes. BSA is a protein derived from bovine blood. In general, although not employed as a drug, a protein derived from animals must be handled with care in consideration of zoonosis (in the bovine, bovine spongiform encephalopathy (BSE), foot-mouth disease, or other diseases). BAS also has problems. For example, since the function of a certain enzyme is readily lost, even when BSA has been added, activity of the enzyme considerably decreases within a few days when the enzyme is maintained at room temperature in the form of solution. Therefore, there is keen demand for development of a stabilizing agent for enzymes which prevents deactivation and inactivation of enzymes, and which does not raise any problem of potential infection with a pathogen of BSE or other diseases.